Pivotal joint



R. W. BROWN PIVOTAL JOINT July 20, 1943.

Filed July 26, 1940 3 Sheets-Sheet l ATTORNEYS July 20, 1943. R. w.BROWN PIVOTAL JOINT Filed July 26, 1940 3 Sheets-Sheet 2 R O T N E V NATTORNEYS July 20, 1943. R. w. B ROWN 2,324,984

. PIVOTAL JOINT Filed July 26, 1940 3 Sheets-Sheet 3 ATTORN EYS- wli,Hun New fg asth ileum Patented July 20, 1943 UNITED STATES PATENT OFFICEPIVOTAL JOINT Roy W. Brown, Akron, Ohio, assignor to The Firestone Tire& Rubber Company, Akron, Ohio, a. corporation of Ohio Application July26, 1940, Serial No. 347,724

Claims.

This invention relates to a pivotal joint. It more particularly relatesto an insulating and pivotal joint having an elastic bushing providedwith a permanently lubricated surface.

One of the major objects of the invention is to provide an improvedpivotal joint which is inexpensive to manufacture, particularly on amass production basis.

Another object is to provide an improved pivotal joint having a minimumof parts and which shown in Figure l; and

will not require adjustment during its useful life. Figures 9 to 12 showsections of further modi- Another object is to provide a pivotal jointfled forms of the invention which are particuhaving a resilientlyyielding characteristic, so larly adapted to spring shackles, torquearms,

that it will have insulating and a controllable steering linkages, andthe like.

amount of shock absorbing properties. 15 Broadly speaking, the presentinvention con- Another object is to provide a pivotal joint of templatesa pivotal connection which is capable the type referred to in which theresiliency or of relative movement about the three planes atadjustability of the bushing can be readily preright angles to eachother and rotational movedetermined during the manufacturing and asmentabout an axis in one or more of the planes.

sembly operations. All of the joints disclosed permit universal piv-Another object is to provide a pivotal joint which will permit relativemovement of the connected parts in the three planes at right angles toeach other and rotational movement while at the same time providingyieldingly resilient centering means to prevent the outer shell orhousing of the joint, from metal to metal contact with the shank of theball and will thereby preclude excessive wear and noise.

Another object is to provide a device of the type referred to abovewhich will be substantially tight against dirt, water, and the likeencountered in normal use.

Another object is to provide an improved pivotal joint having a dynamiccoeflicient of friction greater than the static coefiicientthat is, onein which less force is necessary to initiate movement of the joint thanis necessary to maintain movement.

Other objects will be readily apparent from the following descriptionwhen considered with the accompanying drawings in which:

Figure 1 illustrates the environment of the application of an embodimentof the invention as applied to a typical steering linkage of typicalindependently suspended front wheels of an automotive vehicle;

Figure 2 is a partial section detail of the short linkage shown inFigure 1;

Figure 3 is an enlarged partial plan view of Figure 1 showing analternative construction wherein the outer housing for the pivotal jointis attached to the steering cross link;

Figure 4 is a side elevation of Figure 3;

Figure 5 is a front sectional view on the line otal movement, but someare constructed and arranged to permit more relative movement in someplane, or planes, than in other planes. Furthermore, the inventioncontemplates such a joint in which the two parts of the joint areresiliently urged to an intermediate relative position in order toprevent rattling and excessive wear.

The joint is particularly adapted for use in the steering linkages ofvehicle wheels although it is readily applicable to any type ofmechanical linkage such as, for instance, those used in connection withshock absorbers, spring shackles, transmission shifting mechanisms andthe like.

Some embodiments of the present invention are illustrated as applied tothe steering gear linkages of independently suspended steering wheels inan automobile, typical illustrative examples of this application beingshown in Figures 1 and 2.

Other embodiments are shown as applied to solid axle steering linkages,to spring shackles, torque arms, and the like. It will be readilyunderstood that the relative movement between a steerable wheel and thebody or frame of a vehicle is of a very complex nature. The wheels mustbe capable of pivotal movement about a substantially vertical axis and,at the same time, must be capable of relative vertical movement with thebody, or frame, and must be adapted to move angularly, in general, withrespect to the wheels of the vehicle about axes transverse, as well aslongitudinal, of the vehicle. Any combination of these relativemovements may take place simultaneously. It will be readily understoodthat since the steering mechanism of a vehicle is rigidly attached tothe frame, it is necessary that universal pivotal connections to thesteerable wheels be provided to permit control of the wheels under anyor all of the above conditions. These pivotal joints must permit thenecessary movement and at the same time must be stabilized to preventrattling and excessive wear.

From a practical standpoint the center of mass of the steering linkagesis very seldom, if ever, on the theoretical axis passing through thecenter of the pivotal joints and it will therefore be seen that when thewheels of the vehicle are subjected to very high accelerations invertical directions, such as when the wheel passes over irregularitiesof the road at high speed that a whipping action, that is, anoscillatory rotational movement about a line passing through the centerof the pivotal connections of the linkage will take place. This isparticularly true of steering linkages, such as that shown in Figure 1,where for manufacturing reasons it is necessary that the links be bent,which still further displaces the center of mass from the axis passingthrough the center of the joints. The whipping action of these links isparticularly severe about their end connections. In devices heretofore,this whipping action has caused excessive hammering and wear of the neckof the ball pivot as it strikes the outer casing of the joint, with theresult that the pivotal connection soon became very noisy and had to bereplaced. The further disadvantages of previous constructions is that itis very difficult to provide a satisfactory dirt and water seal aboutthe neck of the ball and, at the same time, permit the full necessaryrange of angular movement in the necessary directions and positions.

Referring specifically to the drawings, an embodiment of the inventionis illustrated as applied at the points 5 to 8, of typical steeringlinkages of a vehicle, as shown in Figure l. The various dottedpositions of the wheels and steering linkages of Figure 1 illustrate thetype of relative pivotal movement to which the joints must be adapted inorder to operate satisfactorily in the applications shown. It is, ofcourse, understood that the pivotal joint may also be adapted toapplications where the range of relative movement is more or lessgreater than that shown, by a mere mechanical change to adapt it to theparticular installation desired.

In general, the pivotal joint I is typical of an embodiment of theinvention and comprises an inner bearing member 2|, illustrated as aball, an outer housing 22, and an intermediate bushing 23, shown inFigure 2, and subsequent figures.

.The ball member 2| may take various forms so long as it has asubstantially spherical bearing surface, and the outer casing 22 mayalso take various forms, the particular alternative constructions beingdisc' :sed in detail hereinafter. The gear member 2| has an integralstud 2|a which may be attacned to one of the pivoted parts. The bushing23 comprises a resilient outer layer of rubber 26, or material havingsubstantially similar properties, and an inner flexible lining 21.

In Figure 2 the outer housing 22 is shown as formed as an integral partof the steering cross link 24, also illustrated in Figure l. The lining21 is preferably made of porous material capable of being impregnatedwith lubricant suificient in amount and having such characteristics thatthe due to uneven road conditions.

joint will be properly lubricated for the full useful life of the joint.The flexibility of the lining 21 and the resiliency of the rubber layer26 gives the joint noise and vibration insulating properties and allowsslight irregularities on the inner bearing member 2|. This eliminatesthe neces sity of machining operations on this part. The inner bearingmember can, therefore, be made of an unmachined metal stamped or forgedpart. In this particular instance the layer 26 is preferably made ofoil-resistant rubber and the lubricated layer 21 is formed of a specialfabric composition which has been impregnated with a suitable lubricant,details of which will be hereinafter set forth. The outer layer 26 hasan integral extension, or skirt 28 extending beyond the housing 22 andsurrounding the shank of the stud on the inner bearing member. The skirt28 terminates in a flange 29 carrying a lubricated disk of liningmaterial 3|, which is a composition similar to the lining 2'! of theball joint. This skirt and flange lining material are resiliently urgedagainst the under surface of an eye 32 on the end of steering link 25and thereby provide a suitable dirt seal to exclude water, dirt orforeign matter from the ball joint.

The bushing 23 is molded and vulcanized to a predetermined form, size,and shape substantially complemental to the inner contour of the housing22 in the link 24 and the ball joint and bushing are inserted throughthe aperture in the lower side of the housing and thereafter theplate-like disk 33 is placed thereover to close same and a flange 34 ispeened over to retain the disk 33 in fixed position.

The lining 21 is preferably fabric, which has been impregnated with alubricant comprising a solid and a liquid, to produce, when infrictional contact with the metal ball, a dynamic coefficient offriction greater than its static coefficient. This is very important anddesirable in steering linkages, because such characteristic greatlyfacilitates a driver in maintaining a desired course at high speedsdespite intermittent external side forces due to Wind and shifting ofthe vehicle With steering linkages having this peculiar frictioncharacteristic there is substantially no extra breakaway effort requiredto initiate steering controlthere is less effort required to initiatesteering movement than is necessary to maintain steering movement. Thispermits an operator to apply a steady, smooth force while changing thesteering angle of the dirigible wheels which is very necessary tomaintain a predetermined course at high speed wtihout; fatigue to thedriver.

For the purpose of providing a stable and rattle-free joint, means maybe provided to urge the shank of the stud 2|a to a central positionrelative to the outer housing. Joint 6 is exactly similar to joint 1 inthis respect, the details of which are shown in Figures 3 to 6. The onlydifference between joints 6 and 'l is that the latter has its housingarranged between the ends of the drag link 24, while in the former, thehousing is at one end of the drag link 25. To this end, the outerhousing 35 of the joint 6 is provided with recesses 36 at diametricallyopposed sides of the housing and the recesses are engaged by lugs 31which are integral with the extension or skirt 28 on the resilientbushing 23 of the joint. The bushing of joint I is exactly similar tothe bushing of joint 6 and therefore the same reference numerals areused. The engagement of the lugs with the recesses prevents relativerotational movement between the housing and the bushing and thereforeprevents chafing of the rubber layer.

The lugs 31 are arranged at substantially right angles to the pivotalaxis of the link 25, which passes through the centers of the ball joints6 and 1 to resist whipping action or the oscillatory movements of thelink 25, due to inertia of the link 25 when the wheel of the vehicle andthe outer end of the link 25 are subjected to vertical oscillations.

As set forth above, functionally and structurally, joints 6 and 1 aresubstantially identical and further common features will be set forthwith reference to Figures 5 and 6 wherein the lower end of rubber layer26 is provided with an annular ring portion 260. of rubber stock softer,when vulcanized, than that of the layer itself. The line of demarcationbetween these two stocks is indicated by the cross-hatching.

During the manufacture of the rubber part the thickness and resiliencyof this ring may be altered so that when disk-like plate 33 is fixed inpredetermined assembled relation the bushing 23 will be placed under apredetermined amount of compression for the purpose of providing a snugfit between the lining 21 and the ball 39. It is to be understood inthis connection, however, that the rubber part 26 is molded to a shapesubstantially complemental to the inside contour of the housing beforeassembling,

and that the amount of compression of the assembled joint is onlysufllcient to maintain a stable joint. The relative position of the ballwith respect to the casing is determined by the shaping of the moldedrubber part and not primarily by the amount of compression to which thelining is subjected.

As shown, the pivotal connection is capable of moving farther in theplane illustrated in Figure 5 than in the plan at right angles thereto,illustrated in Figure 6. The necessity for'this movement in one planeand the limitation in the other plane will be readily understood byreference to the previous general view of Figure 1. It will be notedthat in order to accommodate all of the steering movements for thevarious possible positions of the wheels with relation to the body,greater angular movement will be necessary in some planes than in otherplanes.

As particularly shown in Figure 5, a hollow ball 39 may be substitutedfor the solid ball 2| of Figure 8, if desired, and the hollow space maybe filled with a reserve supply of lubricant composition during theassembly of the universal joint.

Figure '7 shows a further modified form of the invention which may beapplied to the steering mechanism of a vehicle and has the same generalapplication as that shown in Figure 2. In the embodiment shown a draglink I is provided for connecting the two dirigible spindles (not shown)of a vehicle. A headed bolt I5I, having a tapered shank I5Ia fits into acomplementally tapered bore in the drag link I50 and is held in place insuitable manner, as by means of the nut I52,

A steering link I53 has an eye I54, which encompasses a resilientbushing I56 of the same general construction previously described inthat it comprises a rubber outer sleeve I56a and a lining of permanentlylubricated material I561). The lining I56b is in the form of a sleevewhich engages the outer surface of the bolt I5I and flanges I56c andI56d which engage, respectively, the drag link I50 and the head I5Ib ofthe bolt I5I.

' Search Room The inside of the eye I54 is provided with two conicalbores I60 and I6I with their small ends in confronting relation. Thebushing I56 has complemental surfaces engaging the inner surface of theeye I54. For the purpose of preventing relative axial displacementbetween the bushing I56 and the eye I54 an annular recess I62 isprovided, into which an annular central flange I63 on the bushing I56engages. Since the bolt I5I is cylindrical, the conical surfaces I60 andI6I of the eye I54 permits a large range of relative oscillatorymovement between the bolt I5I and the eye I54 in the plane of the axisof the bolt, as well as permitting relative pivotal movement about axespassing through the axis of the bolt, by way of distortion of the rubberbushing I56. Relative oscillatory movement between the bolt I5I and theeye I54 about the axis of the bolt results in frictional movementbetween the lining I56b and the bolt I5I.

The double conical bushing I56 and the surfaces of the eye I54 providesthe desirable damping of the whipping action of the steering link I53which was described in connection with Figure 2. The annular lips I64and I65 on the ends of the rubber bushing I56 are molded in such shapethat when assembled as shown they will be resiliently urged against thedrag link I50 and the bolt head I5Ib, respectively, to serve as dirtseals.

A modified form of the pivotal connection of Figure '7 is shown inFigure 8 in which the central flange I63 of Figure 'I is omitted. Thisbushing I65 has a central cylindrical portion I62a which joins thesmaller ends of the frusto-conical surfaces. The inner contour of theeye member I54a is complemental to the outside contour of the bushing I65. The bushing is molded with recesses or indentations I650. on theinner surface of the bushing to receive and retain excess lubricant. Inother respects this modified form is similar to that of Figure 7.

Further modified forms of the invention are shown in Figures 9 to 12,inclusive, which are generally of the cylindrical type designedprimarily to provide a lubricated pivotal connection on the axis of thecylinder while at the same time serving as an insulator and permitting asmall degree of pivotal movement in planes at right angles to thecylinder axis and about axes at right angles to the axis of the cylinderaxis.

In Figure 9 the invention is shown as applied to a support for anindependently suspended wheel. The parts which are pivotally connectedare a U-shaped member I10 adapted to be secured to a vehicle frame and asupporting arm (not shown) which terminates in an eye IN. A suitable pinor bolt I12 extends through aligned holes in the member I10, the bushingI13 of the present modification being arranged around the bolt. ,Abearing sleeve I15 and washers I16 and I11 are press fit on the boltI12.

The bushing I13 comprises a rubber sleeve I13a and a lining I14 similarin characteristics to the lining I56b of Figure 7, reviously described.The lining has integral flanges II4a. and H41) which respectively engagethe Washers I16 and I11. The bushing I13 is molded with an annularrecess I18 which serves to receive any surplus lubricant. Annularflanges I13b and I130 on the rubber bushing I13 have four bosses I19spaced with respect to each other which engage complemental recesses IBIin the eye IN. The flanges I13b and I will be molded in such free shapethat when assembled as shown they will serve as dirt seals. It will beunderstood from the foregoing that any relative pivotal movement betweenthe member I and the eye I1I will result in frictional movement betweenthe lining I14 of the bushing I13 and the sleeve I15 and washers I16 andI11. Also, any slight pivotal movement about axes at right angles tothis axis will be permitted by distortion of the bushing I13.

Figure 10 shows a construction, in general, similar to that of Figure 9,except that no metal sleeve and washers are provided over the innerpivotal member. The supporting member may be the two legs I85 of achannel member through which extends an inner pivotal member such as apintle I86. This pintle has an integral flange I81 at one side and agroove I88 and locking ring I89 at the other for the purpose of axiallypositioning the legs I85 of the channel member. The member which ispivotally supported on the pintle I 86 may be a suitable wheelsupporting arm (not shown) terminating in an eye I9I A bushing I93 ofthe same construction as that of Figure 9 is arranged between the pintleI86 and the eye I9I and the operation is the same as that previouslydescribed.

Figure 11 shows the bushing similar to that of Figures 9 and 10 appliedto a spring shackle I96. The shackle has a pintle or bolt I91 extendingthrough aligned openings in the shackle links.

An eye I98 of a leaf spring (not shown) is pivotally supported by, andresiliently insulated from the bolt I91 by a pivotal bushing I99 of thetype shown in Figures 9 and 10.

Figure 12 shows the bushing of Figures 9, 10, and 11 applied as apivotal connection and an insulator for a torque arm in a vehiclesuspension. The U-shaped member 20I may be attached to the frame of avehicle in any suitable manner and has aligned apertures in the legs toreceive a bolt 202. The bolt has a stepped head 203 which fits into alarge aperture 204 in one of the legs of the member 20I. The aperture204 is large enough in diameter to permit the insertion and assembly ofa resilient bushing 206 of the type shown in Figures 9, l0, and 11. Thebushing 206 is assembled inside of a cylindrical sleeve 201 which iswelded, or otherwise secured, to an end of a torque arm 208. The bore ofthe sleeve 201 is in axial alignment with the aperture 209 in the torquearm. The operation of this modification is substantially identical tothat of the constructions of Figures 9, 10, and 11.

In the foregoing where reference is made to rubber, it is to beunderstood that this, is by way of example only and is not to beconstrued as a limitation of the invention to the use thereof.

Permanently lubricated as used in specification and claims, means thatthe joint is provided with sufficient lubricant so that in the absenceof damage in the usual use, the joint will be lubricated for'the fulluseful life thereof.

The description which has been given, recites more or less detail ofparticular embodiments of the invention, which is set forth as new anduseful. However, I desire it to be understood that the invention is notlimited to such exact details of construction, because it is manifestthat changes and modifications may be made within the scope of theappended claims, without departing from the spirit of the invention.Also, the invention is not limited to the applications or usesdescribed, but is to be to understood as contemplating all inherent usesor functions.

What is claimed is: 1. In an insulating and pivotal joint an outerhousing member, an inner bearing member having a shank, a resilientbushing member interposed between said outer housing member and saidinner bearing member, said resilient bushing member having an integralextension extending beyond said housing and around said shank,.anelement attached to said shank having bearing surfaces confronting theend of the extension on said bushing member, said extension havingintegral resilient means operatively interposed between said bearingsurface and said housing and mechanically interlocked with the latter toresiliently resist relative pivotal movement between said inner bearingmember and said housing member.

2. An insulating and pivotal joint comprising an outer housing member,an inner bearing member having a shank, resilient bushing memberinterposed between said outer housing member and said inner bearingmember, said bushing comprising a resilient layer and a layer of fibrousmaterial having one face thereof integrally bonded to said resilientlayer and having its remainder impregnated with lubricant, saidresilient bushing having ari"integral'"extension extending be yond saidhousing and around said shank, dis..-

metrically opposed recesses in said housing, and means associated withsaid extension and engaging said recesses to resiliently resist relativepivotal movement between said inner bearing member and said housingmember.

3. An insulating and pivotal joint as set forth in claim 2 in which themeans spaced on opposite sides of the shank for resiliently resistingrelative pivotal movement of the inner bearing member and the outerhousing member are lugs integrally attached to the bushing extension.

4. An insulating and pivotal joint comprising an inner cylindricalmember, an outer cylindrical member, a resilient bushing between saidinner ient bushing and having its remainder impreg- ,mterunmlubltifiagt, and axial thrustmms fixedly associated with said innercylindrical member, said flanges being mechanically interlocked withsaid outer cylindrical member.

in claim 4 in which said bushing and lining has a circumferflntirirecessconfronting the inner cylindrical member for the reception of excesslubricant.

ROY W. BROWN.

and outer member, said bushing having integral 5. An insulating andpivotal joint as set forth .5

CERTIFICATE OF CORRECTION.

Patent m3. 2,521 .,98l July 20, 1915.

ROY W. BROWN It is hereby certified that error a of the above numbered.v patent requiring column, line 614., for "gear" for "wtihout" read--wi.th-out read "plane"; page 11., 'occurrence; and t the ppears in theprinted specification correction asfollows: Page 2, first read"bearing"; and second column, line 55, page5, first column", line LL0for second column, line 6; Istrike out to said Letters Patent shouldcorrection therein that the same may conform to the record of the casein the 'Patent Office.

Signed and sealed-this 7th day of September Pl n" second Henry VanArsdale, (Seal) Acting Commissioner of Patents.

